Brush assembly tool



Sept. 26, 1961 J. F. PERRIN BRUSH ASSEMBLY TOOL Filed March 12, 1958 E J INVENTOR.

Filed Mar. 12, .1958, Ser. No, 720,911 4 Claims. (Cl. 29-283) This invention is a new and useful tool for brush and retainer ring assembly to armatures of cranking motors, of which the following is a specification:

This invention relates to tools and has for its object the provision for a novel device for installing the brush assembly onto the commutator of an armature. It is well known that the installation of brush assemblies on armatures is diflicult with the use of ordinary shop tools and sometimes results in damage to the brushes. The use of my invention provides a means for a very rapid and easy installation of brush assemblies.

The modern starting motor as employed in motor vehicles utilizes a four brush structure for the commutator, such brush assemblies normally being connected or attached to the motor housing and requiring simultaneous spreading of the four spring-pressed brushes along with axial movement of the motor housing onto the starter armature so that the housing may be properly positioned and the brushes moved into proper relationship with the commutator of the armature. Such an operation is awkward at best and often requires the services of two workmen for proper positioning, the alternative constituting a rather tedious and difiicult job when carried out by .one workman. Further, there is a strong possibility that a single workman, in positioning the brushes over the commutator, may damage the brushes or overstress their springs.

It is, therefore, one object of this invention to provide an improved device for spreading commutator brushes to permit their positioning over the commutator of a motor armature, the device being readily mountable upon the shaft of the armature and virtually automatically spreading the brushes to the proper position as the motor housing is moved axially over the armature.

With the above and other objects and advantages in view the invention consists in the details of construction to be hereinafter more fully described and claimed and illustrated in the accompanying drawing, in which:

FIG. 1 is a plan view in elevation of a brush spreader constructed in accordance with this invention,

FIG. 2 is a side elevational view of the spreader,

FIG. 3 is a bottom plan view of the brush spreader,

FIG. 4 is a side elevational view, partially sectioned of the retainer ring tool,

FIG. 5 is a bottom plan view of the tool shown in FIG. 4,

nited States Patent FIG. 6 is an exploded isometric view illustrating the utilization of the brush spreader on the motor armature, and

FIG. 7 is an additional exploded view illustrating the positioning of the brush spreader upon the armature shaft.

My invention consists of a tool of two parts made of steel, iron, aluminum, plastic or other suitable material (FIGS. 1, 2, 3, 4, and 5). Part 1 is basically conical in shape but made with suitable surfaces, 1a and 1b. Also, part 1 has a centrally drilled hole 10 of such size and depth to enable the tool 1 to slide easily onto the armature shaft 6a. Part 1 of the tool is used for installing the brush assembly 3 onto the commutator of the armature 6 by putting the tool on the shaft of the armature and then sliding the brush assembly onto the tool. The tool 1 causes the brushes to open and slide easily into place on the commutator of the armature.

The commutator brush spreader illustrated in FIGS. 1 and 2 of the drawings is in the form of a truncated conical body and has a lower end of circular cross-section with an upper end terminating in a configuration of a generally thickened Z-shaped cross section as indicated by the numeral 7. The outer faces or portions 8 of the parallel parts of said Z-shape are arcuate, conforming to the outer surfaces of the conical body, and as shown in FIG. 6 are adapted to receive one opposed pair of the commutator brushes. The inner sides of said parts define the upper ends of opposed "surfaces la and 1a whichtaper downwardly and outwardly toward the lower end of the cone to merge with the surface thereof and thereby define diametrically opposed, guide grooves 9 having upper portions of approximately V=shaped cross-section and tapering smoothly with rounded corners and edges into the circular lower portion of the brush spreader. Each of the grooves includes the slightly rounded but somewhat fiat bottom portion or surface 1a facing in diametri'c'al opposed directions, and extending downwardly at an angle with respect to the vertical axis of the spreader, each being adapted to receive one of the other opposed pair of the commutator brushes, while the remaining opposed pair of brushes is received by the upper ends of the conical portions or faces 1!: of the brush spreader between the grooves 9 her simultaneous spreading as the brushes are moved onto the commutator. It is noted that the surfaces 1a and the grooves partly defined thereby extend downwardly tram ap-oint on one side or the axis of the body member to a point on the opposite side of said axis.

In use, the brush spreader is positioned upon the upper end of the armature shaft 6a by reception of the shaft within the recess 10, and the motor housing, or the brush spreader revolved, until the brush assembly 3 is properly aligned with the spreader. Such brush assemblies normally include an opposed pair of brushes which, in relaxed position, are positioned a predetermined distance from the center of the brush assembly, interposed with a second pair of diametrically opposed brushes positioned under relaxed conditions somewhat closer to the axis of the assembly. 'In utilizing the brush spreader, the inward pair of brushes are aligned with the grooves 9 in engagement with the surfaces 1a while the outer pair of brushes are aligned with the tapered or inclined surfaces 111. Then, simply by moving the motor housing downwardly over the armature, the brushes will automatically be spread and moved outwardly as they pass over the lower circular end of the brush spreader for further movement over the commutator 6b. The lower end portion of the spreader is greater in diameter than the commutator 6b, and hence the brushes are readily slipped into commutator engaging position without damage to the brushes or the commutator, or over stressing or bending of the brush springs as often occurs when such operation is attempted manually.

Part 2 of the tool 2 is cylindrical in shape and made to assemble into part 1, as shown in FIGS. 2, 4, 5 and 7. The important part of my invention in part 2 is the cylindrical undercut 2a made of such size and depth to provide a seat for the retainer ring 4. In the installation of retainer rings, part 1 serves as a handle for part 2; part 2 guides the ring onto the shaft 5 and slight pressure on the handle 1 causes the ring to open, and slide easily onto the shaft.

From the foregoing description and a study of the drawings it will be apparent that I have provided a simply constructed and consequently inexpensive tool which provides a means for rapid and easy installation of brush assemblies and retainer rings on the armature of cranking motors.

While I have shown and described the preferred embodiment of the invention it is, of course, to be understood that I reserve the right to make such changes in the form, construction and arrangement of details as will not depart from the spirit of the invention or the scope of the subjoined claims.

What I claim and desire to secure by Letters Patent is:

1. A device for spreading commutator brushes including, a generally conical body member having an upper end and a substantially circular base with a recess therein, the body member being provided with a pair of opposed brush receiving grooves tapering downwardly and outwardly from the upper portion of the body member toward the base thereof and merging with the substantially circular base of the body member, each of said grooves extending from a point on one side of the axis of the body member at the upper portion thereof to a point on the opposite side of said axis at the base of the body member.

2. A device for spreading commutator brushes including, a generally conical body member having an upper end and a substantially circular base with a central cylindrical recess therein, the body member being provided with a pair of opposed brush receiving grooves tapering downwardly and outwardly from the upper portion of in, the body member being provided with a pair of opposed brush receiving grooves tapering downwardly and outwardly from the upper portion of the body member toward the base thereof and merging with the substantially circular base of the body member, the upper ends of the grooves having a pair of walls arranged in a V-shaped configuration, one wall of each groove extending downwardly at an angle with respect to the axis of the body and being adapted to receive one'of a pair of opposed commutator brushes, each said one wall of each groove extending from a point on one side of the axis of the body member at the upper portion thereof to a point on the opposite side of said axis at the base of thebody member.

4. A brush for spreading commutator brushes as set forth in claim 3 wherein the pair of brush-receiving walls face in opposite directions, the body member having inclined surfaces disposed between the grooves and adapted to receive one each of a second pair of opposed com mutator brushes.

References Cited in the file of this patent UNITED STATES PATENTS 2,510,206 Barkan June 6, 1950 2,549,602 Hopps Apr. 17, 1951 2,760,258 Reiger Aug. 28, 1956 2,848,798 Davis Aug. 26, 1958 FOREIGN PATENTS 485,518 Great Britain May 20, 1938 

